Is the ISDN local loop digital or analog ?

Question

As the ISDN does terminate with a special NTE like terminal adapter, which converts the analog to digital and vice versa. Does this mean that the backhaul transmission is always analog ?

Answer 1

ISDN is a digital service and is 100% digital.  The only analog part would be on your side where its converted to digital when it hits the line.

Is this a BRI or PRI we are talking about?

Usually when a PRI is used to feed analog service, you would have a device called a channel bank which has 23 or 24 (in the USA, 30 in most other countries) analog ports that you can feed onto the rest of your analog equipment.  The channel bank is where the analog/digital conversion takes place and is usually your equipment (although sometimes supplied by the telco).

Most modern PBX's can hook directly to a PRI without the need for a channel bank.

ISDN=Integrated Switched Digital Network